Combustion and emission characteristics of NH3/CH4/air in a model swirl combustor: Comparison between premixed and non-premixed modes

Tu, Yaojie; Xu, Shunta; Líu, Hao

doi:10.1016/j.ijhydene.2023.01.235

Cited by 10 publications

(8 citation statements)

References 31 publications

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“…Note that the NH 2 * distribution in pure methane combustion and CH* distribution in the pure ammonia combustion are also shown here, which are caused by signals such as H 2 O. This phenomenon also occurred in a previous study . However, the radiance caused by other signals is negligible, which is also described by Pugh et al When the NH 2 * images are compared with OH*, it can be easily found that the NH 2 * radiance is much stronger at the bottom of the combustor, especially under high E NH 3 conditions.…”

Section: Resultssupporting

confidence: 87%

“…This phenomenon also occurred in a previous study. 20 However, the radiance caused by other signals is negligible, which is also described by Pugh et al 31 When the NH 2 * images are compared with OH*, it can be easily found that the NH 2 * radiance is much stronger at the bottom of the combustor, especially under high E NHd 3 conditions. A similar phenomenon was also investigated in a previous study, which is mainly caused by the ammonia decomposition.…”

Section: Direct Images and Blow-offsupporting

confidence: 53%

“…It seems that the combustion method, such as the method of fuel mixing, which is related to the combustor structure, greatly affects the sensitivity of radicals. For instance, the change of peak chemiluminescence intensity is not significant under fuel-lean condition in fully premixed NH 3 /CH 4 swirling flames, while a quite different tendency is shown in non-premixed swirling flames . Since radical distributions closely affect the flame structure and emission characteristics, further improvement in the combustion method is necessary.…”

Section: Resultsmentioning

confidence: 99%

“…19 Despite premixed NH 3 /CH 4 flames, four chemiluminescence intensities (including OH*, CH*, CN*, and NH*) of non-premixed flames were also investigated. 20 The intensity of all species increased as the ammonia fraction increased from 0 to 50% in premixed flames, while most of them showed an opposite trend in non-premixed flames. Similar phenomena also occurred under different equivalence ratio conditions.…”

Section: Introductionmentioning

confidence: 92%

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Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Lai,

Chen,

Zhang

et al. 2024

Energy Fuels

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Recently, ammonia/methane mixtures have been considered as potential alternative fuels. The present study experimentally investigates the blow-off limits, flame structure, and pollutant emission of ammonia/methane mixtures in a partially premixed swirl-stabilized burner. The effects of fuel composition and the equivalence ratio are also studied. The results show that the NH 3 /CH 4 flame can be stabilized at an equivalence ratio of 0.55. The addition of methane has a positive effect on the blow-off limits. For the chemiluminescence profile, the OH* distribution and CH* distribution of NH 3 /CH 4 flames show a similar tendency under various conditions. The peak OH* and CH* radiances monotonically decrease with increasing E NHd 3 , while the maximum NH 2 * shows an opposite trend. The influence of the equivalence ratio on OH* and CH* in the NH 3 /CH 4 flames is negligible. However, when E NHd 3 is 60%, the equivalence ratio has a significant effect on NH 2 *. In terms of pollutant emissions, the peaks of NO and NO 2 emissions are all found around an E NHd 3 of 20%. When the equivalence ratio reaches 1.0, NO and NO 2 emissions are as low as 15 and 10 mg/m 3 , respectively. At the same time, both CO and unburned NH 3 emissions increase. Therefore, further studies on the application of secondary air or improvement of the fuel injection method to improve the combustion efficiency and reduce the pollutant emissions for ammonia combustion are still needed.

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Section: Resultssupporting

confidence: 87%

Section: Direct Images and Blow-offsupporting

confidence: 53%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 92%

See 2 more Smart Citations

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Lai,

Chen,

Zhang

et al. 2024

Energy Fuels

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“…Increasing the thermal conductivity of the porous material decreases NO emission, while increasing the porosity increases NO emissions. Previous studies primarily focused on premixed flame, while Tu et al 24 experimentally compared the characteristics of premixed flames and diffusion flames of NH 3 /CH 4 /Air. It was found that the diffusion flame is more favorable for reducing NO emissions when a wide range of ammonia mixing ratios and equivalence ratios.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on NH₃/H₂/Air Combustion Flow in a Multiple Direct-Injection Combustor

Wu,

Zeng,

Liu

et al. 2023

Energy Fuels

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To investigate the turbulence combustion characteristics of NH 3 /H 2 /Air in a multiple direct-injection combustor, the effects of equivalence ratio and hydrogen mixing ratio on the mixing characteristics of fuel−air in the mixing-nozzles as well as the flame and emission characteristics in the combustor are analyzed numerically. The results show that the spatial mixing deficiency of fuel−air mixture at the mixing-nozzle outlet is below 1% under all circumstances, which indicates that the mixing-nozzle exhibits satisfactory mixing performance and is capable of achieving the premixed combustion. Furthermore, the intensity of gas turbulence at the mixing-nozzle outlet (inlet of the combustor) is primarily affected by the gas flow within the fuel collision zone. Regarding the flame characteristics, the larger equivalence ratio increases the NH 3 concentration (reducing combustion rate), and the larger hydrogen mixing ratio increases the gas turbulence intensity at the mixing-nozzle outlet (increasing gas flow velocity), which disrupts the stabilized combustion. Moreover, the reaction R18, NH 3 + M ⇔ NH 2 + H + M, inhibits NH 3 consumption and the reactions R20, NH 3 + O ⇔ NH 2 + OH, and R21, NH 3 + OH ⇔ NH 2 + H 2 O, promote NH 3 consumption, while R19, NH 3 + H ⇔ NH 2 + H 2 , initially inhibits and later promotes NH 3 consumption, but primarily plays an inhibitory role. Furthermore, reactions R4, NH + H ⇔ N + H 2 , R11, NH 2 + H ⇔ NH + H 2 , and R28, HNO + H ⇔ NO + H 2 , promote the H 2 formation, and R19, NH 3 + H ⇔ NH 2 + H 2 , inhibits the H 2 formation. As for the emission characteristics, R16, NH 2 + NO ⇔ N 2 + H 2 O, and R28, HNO + H ⇔ NO + H 2 , inhibit and promote NO generation in the upstream region of the combustor, respectively, while R36, NO 2 + H ⇔ NO + OH, promotes NO generation in the whole area.

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Experimental and numerical study of combustion and emission characteristics of NH3/CH4/air premixed swirling flames with air-staging in a model combustor

Tu,

Zhang,

Guiberti

et al. 2024

Applied Energy

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Combustion and emission characteristics of NH3/CH4/air in a model swirl combustor: Comparison between premixed and non-premixed modes

Cited by 10 publications

References 31 publications

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Numerical Investigation on NH₃/H₂/Air Combustion Flow in a Multiple Direct-Injection Combustor

Experimental and numerical study of combustion and emission characteristics of NH3/CH4/air premixed swirling flames with air-staging in a model combustor

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Combustion and emission characteristics of NH3/CH4/air in a model swirl combustor: Comparison between premixed and non-premixed modes

Cited by 10 publications

References 31 publications

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH3/CH4

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH3/CH4

Numerical Investigation on NH3/H2/Air Combustion Flow in a Multiple Direct-Injection Combustor

Experimental and numerical study of combustion and emission characteristics of NH3/CH4/air premixed swirling flames with air-staging in a model combustor

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Product

Resources

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Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Blow-Off Limits, Flame Structure, and Emission Characteristics of Lean Partially Premixed Swirl-Stabilized Flames with NH₃/CH₄

Numerical Investigation on NH₃/H₂/Air Combustion Flow in a Multiple Direct-Injection Combustor